Association of Lipoprotein-Associated Phospholipase A2 with the Prevalence of Nonalcoholic Fatty Liver Disease: A Result from the APAC Study

Hepatic steatosis and nonalcoholic fatty liver disease are common and associated with cardiometabolic risk in a primary prevention cohort of people with HIV

BACKGROUND

Hepatic steatosis, including nonalcoholic fatty liver disease (NAFLD), is common among people with HIV (PWH). We present baseline steatosis prevalence and cardiometabolic characteristics among REPRIEVE substudy participants.

METHODS

REPRIEVE is an international, primary cardiovascular disease prevention, randomized, controlled trial of pitavastatin calcium vs. placebo among 7769 PWH ages 40-75 years on antiretroviral therapy (ART) and with low-to-moderate cardiovascular risk. A subset of participants underwent noncontrast computed tomography, with hepatic steatosis defined as mean hepatic attenuation less than 40 HU or liver/spleen ratio less than 1.0, and NAFLD defined as steatosis in the absence of frequent alcohol use or viral hepatitis.

RESULTS

Of 687 evaluable persons, median age was 51 years, BMI 27 kg/m 2 , CD4 + T-cell count 607 cells/μl; 17% natal female sex, 36% Black, 24% Hispanic, and 98% HIV-1 RNA less than 400 copies/ml. Hepatic steatosis prevalence was 22% (149/687), and NAFLD 21% (96/466). Steatosis/NAFLD prevalence was higher in men and with older age, non-Black race, and higher BMI and waist circumference. Both were associated with BMI greater than 30 kg/m 2 , metabolic syndrome components, higher atherosclerotic cardiovascular disease (ASCVD) risk score, HOMA-IR, LpPLA-2 and hs-CRP, and lower high-density lipoprotein cholesterol. Of HIV-specific/ART-specific characteristics, only history of an AIDS-defining illness was more common among persons with steatosis/NAFLD. After adjusting for age, sex and race/ethnicity, BMI greater than 30 kg/m 2 , HOMA-IR greater than 2.0, Metabolic syndrome and each of its components were associated with NAFLD prevalence.

CONCLUSION

In this cohort with controlled HIV and low-to-moderate cardiovascular risk, hepatic steatosis and NAFLD were common and associated with clinically relevant metabolic and inflammatory disturbances but not current HIV-related or ART-related factors.

Bidirectional association between NAFLD and gallstone disease: a systematic review and meta-analysis of observational studies

BACKGROUND

Growing evidence indicates an association between NAFLD and gallstone disease (GD), while some does not support this. The aim of this meta-analysis was to evaluate the bidirectional association between NAFLD and GD.

RESEARCH DESIGN AND METHODS

Five electronic databases were searched from inception to May 2022. The association was analyzed based on the odds ratio (OR) and 95% confidence interval (CI) with Reviewer Manager 5.3.

RESULTS

Ten studies involving 284,512 participants met the criteria for GD predicting the onset of NAFLD. GD patients had a higher incidence of NAFLD (OR:1.48, CI:1.32-1.65, p < 0.00001), especially the incidence of moderate-to-severe NAFLD (OR:1.63; CI:1.40-1.79), with females at a higher risk (OR: 1.84; CI: 1.48-2.29). The inverse association was explored in eight studies involving 326,922 participants. The GD incidence in NAFLD patients was higher (OR:1.71, CI:1.63-1.79, p < 0.00001) and may increase due to female sex (OR: 4.18; CI: 1.21-14.37) and high BMI (OR: 1.80; CI: 1.36-2.56), compared with the non-NAFLD group. Besides, this bidirectional association was also confirmed in the Chinese population.

CONCLUSIONS

The findings supported positive concurrent and bidirectional relationships between NAFLD and GD. Therefore, clinicians may alert the possibility of NAFLD in patients with GD and vice versa.

2019 Global NAFLD Prevalence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The increasing rates of obesity and type 2 diabetes mellitus may lead to increased prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to determine the current and recent trends on the global and regional prevalence of NAFLD.

METHODS

Systematic search from inception to March 26, 2020 was performed without language restrictions. Two authors independently performed screening and data extraction. We performed meta-regression to determine trends in NAFLD prevalence.

RESULTS

We identified 17,244 articles from literature search and included 245 eligible studies involving 5,399,254 individuals. The pooled global prevalence of NAFLD was 29.8% (95% confidence interval [CI], 28.6%-31.1%); of these, 82.5% of included articles used ultrasound to diagnose NAFLD, with prevalence of 30.6% (95% CI, 29.2%-32.0%). South America (3 studies, 5716 individuals) and North America (4 studies, 18,236 individuals) had the highest NAFLD prevalence at 35.7% (95% CI, 34.0%-37.5%) and 35.3% (95% CI, 25.4%-45.9%), respectively. From 1991 to 2019, trend analysis showed NAFLD increased from 21.9% to 37.3% (yearly increase of 0.7%, P < .0001), with South America showing the most rapid change of 2.7% per year, followed by Europe at 1.1%.

CONCLUSIONS

Despite regional variation, the global prevalence of NAFLD is increasing overall. Policy makers must work toward reversing the current trends by increasing awareness of NAFLD and promoting healthy lifestyle environments.

Advances in paediatric nonalcoholic fatty liver disease: Role of lipidomics

Due its close relationship with obesity, nonalcoholic fatty liver disease (NAFLD) has become a major worldwide health issue even in childhood. The most accepted pathophysiological hypothesis is represented by the “multiple hits” theory, in which both hepatic intracellular lipid accumulation and insulin resistance mainly contribute to liver injury through several factors. Among these, lipotoxicity has gained particular attention. In this view, the pathogenic role of different lipid classes in NAFLD (e.g., sphingolipids, fatty acids, ceramides, etc.) has been highlighted in recent lipidomics studies. Although there is some contrast between plasma and liver findings, lipidomic profile in the NAFLD context provides novel insights by expanding knowledge in the intricate field of NAFLD pathophysiology as well as by suggesting innovative therapeutic approaches in order to improve both NAFLD prevention and treatment strategies. Selective changes of distinct lipid species might be an attractive therapeutic target for treating NAFLD. Herein the most recent evidence in this attractive field has been summarized to provide a comprehensive overview of the lipidomic scenario in paediatric NAFLD.

Association of PAF and its metabolic enzymes with GGT and the Fatty Liver Index in healthy volunteers

BACKGROUND

Platelet-activating factor (PAF) is a lipid inflammatory mediator implicated in liver disease. Its main biosynthetic enzymes are cytidine diphosphate (CDP)-choline:1-alkyl-2-acetyl-sn-glycerol-cholinephosphotransferase (PAF-CPT) and acetyl-coenzyme A: lyso-PAF-acetyltransferases (Lyso-PAF-AT), while PAF acetylhydrolase (PAF-AH) and lipoprotein-associated phospholipase A2 (Lp-PLA2) degrade PAF.

OBJECTIVE

To explore the relation of PAF metabolism with liver diseases and non-alcoholic fatty liver disease, as reflected by the fatty liver index (FLI).

METHODS

In 106 healthy volunteers, PAF concentration, the activity of its metabolic enzymes, and gamma-glutamyl transferase (GGT) were measured in whole blood, leukocytes, and serum, respectively, and the FLI was calculated. Partial correlations and linear regression models were used.

RESULTS

In males, serum GGT activity was positively correlated with abdominal fat (as assessed by analysis of a manually defined region of interest in dual-energy X-ray absorptiometry), triacylglycerols, bound-PAF, and Lp-PLA2, while the FLI was positively correlated with Lp-PLA2 activity. In females, serum GGT activity was negatively associated with high-density lipoprotein cholesterol (HDL-C) (age-adjusted correlations, all p<0.05). Lp-PLA2 was a significant determinant of serum GGT activity in males after controlling for age, low-density lipoprotein cholesterol (LDL-C), and abdominal fat. The addition of bound-PAF in the model significantly increased the explained variance of serum GGT activity (total variance explanation 30%).

CONCLUSION

Bound-PAF and Lp-PLA2 activity predicted serum GGT activity, while Lp-PLA2 was also related to FLI. Our findings shed light on the metabolic pathways linking Lp-PLA2 to other atherosclerosis and/or oxidative markers, such as HDL-C, LDL-C, GGT, and FLI, and underline the important role of PAF.

Lipidomics in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disorder in Western countries, comprises steatosis to nonalcoholic steatohepatitis (NASH), with the latter having the potential to progress to cirrhosis. The transition from isolated steatosis to NASH is still poorly understood, but lipidomics approach revealed that the hepatic lipidome is extensively altered in the setting of steatosis and steatohepatitis and these alterations correlate with disease progression. Recent data suggest that both quantity and quality of the accumulated lipids are involved in pathogenesis of NAFLD. Changes in glycerophospholipid, sphingolipid, and fatty acid composition have been described in both liver biopsies and plasma of patients with NAFLD, implicating that specific lipid species are involved in oxidative stress, inflammation, and cell death. In this article, we summarize the findings of main human lipidomics studies in NAFLD and delineate the currently available information on the pathogenetic role of each lipid class in lipotoxicity and disease progression.

Energy Intake and Plasma Adiponectin as Potential Determinants of Lipoprotein-Associated Phospholipase A2 Activity: A Cross-Sectional Study

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂ ) is associated with increased risk of cardiovascular diseases (CVD) and type 2 diabetes mellitus. Lp-PLA₂ activity is positively associated with male sex, Caucasian race, the presence of metabolic syndrome (MetS) and low-density lipoprotein (LDL)-cholesterol, but it is negatively associated with high-density lipoprotein (HDL)-cholesterol. Associations with other cardiometabolic risk factors, inflammation markers, and lifestyle factors are few or inconsistent. We investigated potential determinants of Lp-PLA₂ activity among both nonmodifiable and modifiable CVD risk factors in a middle-aged Greek cohort without overt CVD. Two hundred eighty four subjects (159 men, 53 ± 9 years and 125 women 52 ± 9 years) participated in a cross-sectional study carried out during 2011-2012 in Athens, Attica. Cardiometabolic risk factors, inflammation markers, lifestyle factors, and Lp-PLA₂ activity were evaluated with established methods. The American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) criteria were used to define MetS. Lp-PLA₂ activity was not associated with MetS, but was associated with MetS components, markers of liver function, and macronutrient intake. Increased total energy intake was associated with increased Lp-PLA₂ activity (odds ratio, 95% confidence interval: 1.07, 1.01-1.14 and 1.10, 1.03-1.16 for the 4th and 3rd quartiles, respectively, compared to the 1st quartile) after adjustments for sex, pack-years of smoking, LDL-cholesterol, and statin treatment. Adiponectin tended to be inversely associated with Lp-PLA₂ activity (0.91, 0.82-1.00, and 4th versus 1st quartile). Our results suggested that total energy intake and adiponectin levels are potential determinants of Lp-PLA₂ activity.

Lipoprotein-associated phospholipase A2: The story continues

Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular inflammation through the regulation of lipid metabolism in blood, thus, it has been extensively investigated to identify its role in vascular inflammation-related diseases, mainly atherosclerosis. Although darapladib, the most advanced Lp-PLA2 inhibitor, failed to meet the primary endpoints of two large phase III trials in atherosclerosis patients cotreated with standard medical care, the research on Lp-PLA2 has not been terminated. Novel pathogenic, epidemiologic, genetic, and crystallographic studies regarding Lp-PLA2 have been reported recently, while novel inhibitors were identified through a fragment-based lead discovery strategy. More strikingly, recent clinical and preclinical studies revealed that Lp-PLA2 inhibition showed promising therapeutic effects in diabetic macular edema and Alzheimer's disease. In this review, we not only summarized the knowledge of Lp-PLA2 established in the past decades but also emphasized new findings in recent years. We hope this review could be valuable for helping researchers acquire a much deeper insight into the nature of Lp-PLA2, identify more potent and selective Lp-PLA2 inhibitors, and discover the potential indications of Lp-PLA2 inhibitors.

Association between Helicobacter pylori infection and non-alcoholic fatty liver disease in North Chinese: a cross-sectional study

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease. Previous studies on the association between Helicobacter pylori (HP) infection and NAFLD are inconsistent. Our study was aimed to find out the relationship between HP infection and NAFLD. We performed a large cross-sectional study in northern Chinese adults in 2015. ¹³C-urea breath tests were used to determine HP infection status. Abdominal ultrasonography was performed to diagnose NAFLD. Multivariable logistic regression was conducted to identify the association between HP infection and NAFLD. A total of 4081 individuals were included in this study; 2137 (52.36%) participants were HP-positive, and 1022 (47.82%) were diagnosed with NAFLD in HP-positive individuals. The odds ratios (OR) and 95% confidence intervals (CI) of participants with HP infection for NAFLD were 1.20 (1.06–1.36) in crude model and 1.27 (1.07–1.50) in fully adjusted model. When stratified by sex and dyslipidemia, the fully adjusted OR and 95% CI for NAFLD were 1.22 (1.10–1.80) in females and 1.44 (1.18–1.75) in subjects with dyslipidemia. There were not significant increased OR for NAFLD when stratified by age. The study indicate that HP infection is associated with NAFLD, particularly in females and patients with dyslipidemia, suggesting that HP eradication might be an alternative method for the prevention or treatment of NAFLD treatment.

Relationship between Lp-PLA2 and Child-Pugh classification in patients with hepatitis B cirrhosis

AIM

To investigate the association between serum lipoprotein related phospholipase A2 (Lp-PLA2) level and Child-Pugh classification in patients with hepatitis B cirrhosis.

METHODS

A total of 269 patients with hepatitis B cirrhosis were selected as a case group, 157 patients with chronic hepatitis B selected as a disease control group, and 120 healthy subjects as a normal control group. Cirrhotic patients were divided into groups A, B, and C according to Child-Pugh classification. The venous blood was collected from each group and serum Lp-PLA2 level was detected by immunoturbidimetry. After propensity score matching (PSM), statistical analysis was performed to compare serum Lp-PLA2 levels between different groups.

RESULTS

The level of serum Lp-PLA2 was significantly higher in the liver cirrhosis group C (443.1 ng/mL ± 40.6 ng/mL) than in the liver cirrhosis groups A (208.5 ng/mL ± 84.6 ng/mL) and B (390.5 ng/mL ± 42.3 ng/mL) and the chronic hepatitis B group (154.3 ng/mL ± 54.1 ng/mL) (P < 0.01), in the liver cirrhosis group B than in the liver cirrhosis group A and the chronic hepatitis B group (P < 0.01), and in the liver cirrhosis group A than in the liver chronic hepatitis B group (P < 0.01). Similar results were also found between the chronic hepatitis B group and the healthy control group (119.1 ng/mL ± 19.8 ng/mL) (P < 0.01). The ROC curve showed that when chronic hepatitis B was used as the control group, the area under the ROC curve of liver cirrhosis was 0.852, and the diagnostic threshold was 262.5 ng/mL. When cirrhosis grade A was used as the control group, the area under the ROC curve of cirrhosis grade B was 0.969, and the diagnostic threshold was 311.5 ng/mL. When cirrhosis grade B was used as the control group, the area under the ROC curve of cirrhosis grade C was 0.809, and the diagnostic threshold was 420.5 ng/mL.

CONCLUSION

The level of serum Lp-PLA2 increases with the progression of hepatitis B cirrhosis, which is helpful for judging the Child-Pugh classification of patients with hepatitis B cirrhosis. Serum Lp-PLA2 level can be used as a reference index for monitoring the course of hepatitis B cirrhosis.